Current issues with communicating data over a wireless network can include low throughput, frequent handovers, handover failures, inefficient offloads, and service interruptions.
Dual connectivity (DC) in an LTE network can significantly improve per-user throughput, reduce handovers, and reduce handover failures by allowing a user to be connected simultaneously to a master cell group and a secondary cell group via a macro evolved Node B (eNB) and a small cell eNB.
With regards to low throughput, dual connectivity can increase per-user throughput by aggregating radio resources from at least two eNBs. Additionally, throughput can be increased by transmitting or receiving multiple streams and dynamically adapting to the best radio conditions of multiple cells. Also, small cell eNBs can provide additional capacity for UEs having multiple radio connections.
Moreover, moving UEs suffer frequent handover failure, inefficient offload, and service interruption. The consequences are more severe if the UE's velocity is higher and cell coverage is smaller. Dual connectivity can reduce the handover failure rate by maintaining the macro eNB (e.g., primary cell) connection as the coverage layer. Dual connectivity also helps in load balancing between the macro eNB and the small cell eNB (e.g., secondary cell).
Furthermore, dual connectivity can reduce signaling overhead towards the core network due to frequent handover. For example, signaling overhead can be reduced by not issuing handover operations as long as the UE is within macro coverage.
However, dual connectivity can impose several technical challenges.